Time-delay attachment for wall switches



May 5, 1953 c. H. BRAcKl-:N

TIME-DELAY-ATTACHMENT FOR WALL SWITCHES Filed April 15, 1952 PatentedMay 5, 1953 OFFICE TIME-DELAY ATTACHJHENT FR WALL SWITCHES Clement H.Bracken, Pacoima, Calif.

Application April 15, 1952, Serial No. 282,438 6 Claims. (Cl. 200-34)This invention relates to a mechanism adapted for attachment to anelectric switch of the wallmounted, toggle type, for tripping the switchat the conclusion of a pre-determined time interval. Many instancesarise in which it would be desirable to operate a switch of the typereferred to, by a means that will act automatically and withoutrequirement of the physical presence of the user. For example, manyhomes are equipped with outside lights, for the purpose of lighting adark driveway, and one leaving the home with the intention of using thedriveway is required to switch on the outside light, drive hisautomobile out of the driveway, and then leave the'vehicle for thepurpose of switching oi the light. This is only one instance in which amechanism of the type stated is desirable, and in recognition of theneed for such amechanism, previous 1 switch attachments Aand switchconstructionshave been devised for this purpose.

' However, those mechanisms previously devised along this line, of whichI have knowledge, have not, so far as is known, found wide commercialfavor. This, I believe, may be due to the fact that in some instances, acomplete replacement of the conventional wall switch must be vmade, forsubstitution of anew switch having 'a time delay mechanism incorporatedtherein. In other instances of which I have knowledge, though themechanisms are attachable to conventional wall switches, they do nothave means incorporated therein for permitting a user to preset the timeinterval during which the switch is to remain unaffected by the device.

Accordingly, it is one important object of the present invention toprovide a time delay attachment for wall switches which can be securedto any conventional toggle switch merely by removal of the screwsconventionally employed for securing the switch cover plate in place,and by subsequent attachment of the` device to said cover plate by means`of said screws.

It is another important object to provide a mechanism as described whichwill be so designed as to permit the user to preset the time intervalduring which throwing ofthe switch is to be delayed.

Yet another object of importance is to provide a device of the characterreferred to so designed as not to interfere, in any way, with normaioperation of the switch.

Yet another object of importance is to provide a. mechanism as statedwhich will be of hydraulic construction, the mechanism being so designedas to cause the opposed pressures of a spring and a quantity of pressureuid to act upon the switch tripping means in a manner effective to delaythrowing of the switch handle by said means.

Still another object of importance is to pro- :sor

vide a time delay attachment for wall switches which, after being usedfor the purpose of causing a switch operation after a delayed period,can be reset with maximum ease and facility.

summarized briefly, the invention includes a cylinder adapted to retaina quantity of pressure fluid and having means at one end whereby thecylinder can be attached readily to the cover plate of a conventionalwall-mounted, toggle switch. A piston is slidably mounted in thecylinder, and isurged in one direction by a spring interposed betweenthe piston and said end 'of the cylinder. The piston, inthis connection,is provided with a restricted port, so as to slowthe movement of thepiston, vdue to resistance on the part of the fluid, when the springurges the piston in said direction. Means is provided, however, in thepiston that will allow free movement of the piston in an oppositedirection, for resetting of the mechanism. A shaft is slidable withinthe piston, and has means at one end adapted to engage the projectinghandle of the toggle switch. In operation, the piston travels in saiddirection within the cylinder, the shaft and piston having means whichwill be effective to cause joint movement of the shaft and the pistonafter a predetermined time interval, for tripping of the switch. Theshaft, in this connection, can be disposed in either of two positionsrelative to the piston, in one of which the movement of the piston isslower than it is in the other position, due to a means provided on theshaft for controlling the rate of fluid flow past the piston. In theother position of the shaft and piston, said means on the shaftcooperates with the restricted orice of the piston to accelerate thepiston movement, thereby to shorten the delayed time interval duringwhich the switch awaits actuation by the device.

Other objects will appear from the following description, the claimsappended thereto, fand from the annexed drawing, in which like referencecharacters designate like partsthroughout the several views, andwherein:

Figure 1 is a front elevational view of a time delay attachment for wallswitches formed in accordance with the present invention, as it appearswhen mounted upon a conventional switch; "Figure 2 is alongitudinalsectional view, taken vsubstantially on line 2-2 of Figure1;

' Figure 'i s a sectional view taken transversely of the device, on line3--3 of Figure 1; y

Figure 4 isr a transverse sectional view through the cylinder of thedevice, taken on line 4 4 of Figure 2; and

Figure 5 is a longitudinalsectional view through the inner end portionof the shaft element taken on line 5 5 of Figure 2.

Referring tothe drawings in detail, W represents the wall of a room,building, or the like,

3 said wall having mounted thereon a conventional toggle switch havingthe usual cover plate Ill, and a switch handle I2.

'I'he device constituting the present invention includes a rectangularvmounting plate I4, said plate being flat so as to be positioned againstthe nat cover plate I0, and being formed with a center opening I5through which the switch handle I2 extends.

The wall switch is provided with the usual screws whereby the coverplate is secured to the receptacle, not shown, ordinarily associatedtherewith, and for the purpose of mounting the device said screws areremoved, the mounting plate I4 being formed with vertically spacedopenings respectively adapted to register with the screw receivingopenings of the cover plate l0 of they switch.

When the screws are returned to their proper openings, one screw,designated by the reference numeral I6, is disposed with its head in afully countersunk. position within the mounting plate, while the otherscrew, designated by thev reference numeral i8, is so arranged as tohave its head projecting partially from the mounting plate A(see Figure2), for a purpose to be made presently apparent.

Fixedly secured in a suitable mannerl to the lower Vend portion of themounting plate t4 is a pair of spaced, nat, arms 26', said arms Vhavingspaced apart, (Figure l). Thisin eiiect forms a dovetailed groove,adapted to vslidably receive the dovetail tongue 2li integrally formedupon the upper surface of a circular cap 26'. The capZG isalso-1integral a depending, externally threaded extension 2B. the bottomsurface of. whichha's a centrally disposed concavity 36. At the centerof the` concavity, the cap. 26 is formed, with a depen-ding boss 32v thefree end of which projects beyond y ther depending extension 28.

A center opening 34 is. formed in the cap, said opening extending fullytherethrough `and being in communication,r as best shown in Figure 2.,with a laterally extended vent 36.. The upper end portion of, theopening 34, as will be noted from the drawings, is of enlarged diameter,so as to cause said vent 36. to be in communication withI atmosphereduring the operation of the mechanism.,

An elongated cylinder 38 is internally threaded at. its upper end` forengagement with the threads of the extension 218, a sealing gasket 36being interposed between the cap and cylinder for the purpose of sealingthe cylinder against leakage.

The cylinder contains a quantity of pressure A Mounted slide-bly withinthe cylinder is a piston, 4.2, said piston having its side wall formed,intermediate the upper and'lower surfaces, ofthe piston, withl anannular groove in which is seated a sealing ring M that has wipingcontact with the inner surface of the cylinder.

spaced inwardly a short distance from the'v periphery ofi the, piston isan annular series of equidistantly spaced'v apertures, 46 (Figures 2"and 4) and on the'bottoin end of the cylinder there isl provided adepending, circumferentially grooved projection on which is mounted acentrall'y apertured, circular outlet valve 56 formed, of a flexiblematerial. The marginal portion of the outlet valve, as will be notedfrom Figure: 2, isada'pt'ed t'o close' `the lower ends of the apertures;46, and vthus 'it will be seen that the Aoutlet valve acts as a checkValve for each aperture 4'6", miliare--v by to close said apertures whenthe piston lf2 is oppositely beveled inner edges '22 `thus to open saidapertures and permit free movement of the piston in said returndirection thereoi.

It will be understood, in this connection, that the valve lne'ed not, inevery instance, be formed of a flexible material, since said valve, ifpermittedmovement on its associated projection 48 longitudinally of thecylinder, can move into and out 'of engagement with the underside of thepiston for the purpose of discharging its intended functions in a propermanner.

Formed `centrally in the piston 412` .is a port52, saidportopening atone end through the 4projection liti, and. opening at its other endthrough an upstanding boss 54 Vprovided upon the piston.

A piston .actuating spring 56 is of the coil type, and at .its lower endis circumposed about the boss 5 4 of the piston, in engagement with theupper surface ot. the piston. At its upper end, the spring 56iscircumposed about the depending boss 32 ofthe .cap 2li.. Thus, thespring 56, when compressed, tends to urge the piston 42. downwardly thecylinder 33.

The invention. vincludes an elongated shaft 58, said shaft beingslidabl'y mounted in. the .cap 24 and having one end portion disposedwithin the cylinder. Said end portion of the shaft extends throughtheport 52 of the piston 42, being loosely positioned within. said portas will be noted from Figure. i?E 'f As a-result, the port 52isrestricted iny area, so 'that 'nid flowing `past the piston ondownward movement of' the piston will,.by reason oi' itsrbeinglcompelled to pass through the restricted 'port 52, causer the movementof the piston under the pressure of the spring 56 to. be slowedconsiderably.

On the lower .end of the shaft 5.8y is a circuinterential collar 6E,said. collar forming an. abutment` on the shaft onwhich is seated aspring 62..

That end of the shaft 58, onA which the `abut-- ment `6i] is formed hasan elongated, axial recess 64 (Figure 5),. and. .communicating betweenthe inner 'end of said recess and the interior of the. cylinder, throughthe side. wall oi'. the shaft Y58, is an orice 66.

The other end of the shaft projects upwardly beyond the cylinder asubstantial distance, and. carries a block` 68 having a recess Itreceiving the shaftthe shaft having a cross pin 'lZwhereby the block 68is pivo'tally mounted. upon the shaft.A The. block 66, as will be vnoted.from Figure 2,v has a flat end' surface, lll which, in .one position otthe block, will clear the projecting head of the screw I6, but whichwill hook under said head in another position to which the. block ispivoted.

In use, and assuming that a long time. interval is .desired before theswitch handle I2 is. thrown,

the shaft Ellis pulled upwardly to its maximum extent. This, will causethe piston 42 to be pulled upwardly to such an, extent 'as tosubstantially close. the, convolutions; ofk the spring, 5.6,. with, allthe fluid being disposed below the piston, showngin Figure 2.'lll*1e1'1,l the user presses the shaftv '58 downwardly to such anextent as to cause the block 68 to be disposed just below the head ofthe upper screw Il S- 'Theswitch handle r2 is then thrown manually toits 'up or on position.

y The spring 56 tending to expand, will nowiuge the piston '42downwardly within the cylinder., and this downward movement will beslowedv by the uid 40 in the manner hereinbefore described. After thepiston has traveled downwardly along the shaft 58 for a predetermineddistance, it will engage the upper end of the spring 62, and this willbe effective to begin a slow downward movement of the shaft 58, jointlywith the continued downward movement of the piston.

The block 68 will now come'into engagement with the switch handle I2 andmovement of the shaft 58 will be temporarily halted by said switchhandle. The spring 62, of course, is weaker than the spring 56, so themovement of the piston will continue after the movement of the shaft istemporarily halted. This causes the piston to move past the orifice 66,and the rate of flow of fluid past the piston will now be increased,since fiuid will flow both through the restricted port 52 and theorifice 66. This changes the relation of the pressure of the spring 56to the resisting pressure offered by the fluid 40, so as, in effect, toincrease the pressure of the spring 56. Increased spring pressure,transmitted through the spring 62 and abutment 60, will cause the switchhandle to be tripped, so as to operate the switch after the desired timeinterval.

If it is desired to shorten the time interval, the user pulls the shaft58 upwardly to its full extent, so as to cause the block 68 to bedisposed a substantial distance above the projecting head of the screwI8, with the spring 62 in engage-A that fiuid will flow past ther pistonmore readily than would be the case if the fluid could pass only throughthe restricted orifice 52.

As a result, the speed of movement of the piston 42 is accelerated, andsaid piston will travel downwardly within the cylinder at va Somewhataccelerated pace, carrying the shaft 58 therewith. When the block 68engages the upper end of the switch handle I2, once again, the movementof the shaft 58 will be temporarily halted, with the piston 42 movingfully past the orifice 66. The final action of tripping the switchhandle I2 is the same as in the first instance.

It may be noted that the block 68 is so arranged as to engage the switchhandle I2 at the outer end of said handle, thus to increase the leveragedesired for tripping of the switch.

It is also believed Worthy of note that the device can be attachedreadily to a wholly conventional, wall-mounted, toggle type switch, withlittle difficulty. It is also believed to be an irnportantcharacteristic of the invention thatfthe user is enabled to preset thetime interval, so asv to accelerate the trippingl of the switch if hesov desires.

The entire device, as will be noted, is of relatively simpleconstruction, and in this connection, it will be understood that withinthe scope of the claims appended hereto, the cylinder could be formed invarious ornamental or inconspicuous designs, to harmonize with theinterior of the structure in which the device isY being used. The devicecan, of course, be used exteriorly of a building if it is so desired. l

It may be noted that the device does not interfere with normal operationof the switch, when it is not desired to use the device. In suchinstances, the shaft 58 is rotated 180 degrees from the position thereofshown in Figure 2, and the underside of the block 68 is allowed to restupon the tongue 24. This leaves the switch handle I2 lfully exposed, andunobstructed by the device, to

for any purpose to which it may be suited. Nor

is the invention to be necessarily limited to the specific'constructionillustrated and described, since such construction is only intended tobe illustrative of the principles of operation and the means presentlydevised to carry out said principles, it being considered that theinvention comprehends any minor change in construction that may bepermitted within the scope of the appended claims.

What is claimed is:

' 1. In a time delay attachment for Wall switches of the toggle type, acylinder having a quantity of pressure fiuid therein; a piston workingin the cylinder, said fluid and piston being relatively arranged to slowmovement of the piston in one directionv within the cylinder; a shaftslidably mounted in one end of the cylinder, said shaft having one endextending into the cylinder and the piston having a slidable mounting onsaid end of the shaft; means on the shaft engageableV by the piston,after slow movement of the piston in said direction longitudinally ofthe shaft over a predetermined distance, for effecting joint, slowmovement of the shaft and piston; a spring engaged between one end ofthe cylinder and piston, said spring being tensioned to urge the pistonin said direction; and means on the shaft adapted to engage and trip thehandle of a wall switch aftersaid slow movement of the shaft over apredetermined distance. Y

2. In a time delay attachment for wall switches of the toggle type, acylinder having a quantity of pressure fluid therein; a piston slidablein the cylinder, vsaid piston having a port for the passage of fluidtherethrough and said port being of a restricted size so as to slowmovement of the piston in one direction within the cylinder; a shaftslidably mounted in one end of the cylinder, said Shaft having one endextending into the cylinder and the piston having a slidable mounting onsaid end of the shaft; means on the shaft engageable by the piston afterslow movement of the piston in said direction over a predetermineddistance, for effecting joint, slow movement of the shaft land pistonthereafter; a spring' interposed between one end of the cylinder and thepiston, said spring being tensioned to urge the piston in saiddirection; and means on the other end of the shaft adapted to engage andtrip'the handle of a wall switch after said j slow movement of thepiston Iand shaft over a predetermined distance.

3. `In 'a time delay'attachment for wall switches of the toggle type, acylinder having a quantity of pressure fluid therein; a piston slidableinthe cylinder, said piston having a port for the passage of fluidtherethrough and said port being of restricted size to slow movement ofthe piston in one direction within the cylinder; a seriesof check valvedapertures in thepiston arranged to permit free movement thereof in anopposite direction; a shaft slidably mounted in one end of the cylinder,said shaft having one end portion extending into the cylinder andloosely positioned through said port, for slidable mounting of thepiston on said end portion of the shaft; means on the shaft engageableby thepiston after slow movement of the piston along the shaft in saidone direction over a predetermined distance, for

fantasmas piston ythereafter in the same direction; afspring interposedbetween one end foif't'he rcylinder 'and :the piston, said spring beingtensioned to urge 4the piston in saidonedirection; and lmeanso1i rvtheother endportion'of the shaft-.adaptedvto env'gage and trip thehandlefof a wall switch after said slow movement 'of the piston and lthe shaft'over yaf predetermined distance. f

4. 'In a time delayattachment-for wallswitches of theftoggle Itype, acylinder .having ya .quantity -ofipressure -)fluidi-,herein; a pistonsldableiin the cylinder, said pistcnnavng a port-for ythe 'passage of=fluid Ytherethroughandisaid port being of a restricted size to slowmovementof the piston in one direction Within the cylinder; a series ofcheck valved apertures in the piston arranged to permit zfree movementthereof in .anopposite direction; `a shaft slidablyrnountedin Yone `endof the cylinder, said .shaft having one end .portion extendingintofthe'cylinder and looselypositioned through .said port,.forslidablemounting ofthe piston on saidfendportion of the shaft; anlabutmentionsaid endportion vofthe shaft; ;.a :rst

springcircumposed aboutfthe shaft and'seated on saldabutment, saidspring being engageable. by the ypiston l.a1`te1..s'lovv movement ofthepiston along the shaft insaid one direction for effecting joint, slow.movement of the shaft and piston thereafter in thesamedirection; asecond .spring interposed between .one end ofthe cylinder and thepiston, said-second spring being tensionedto urge'theipistonin said onedirection; and :means ori-the other end portion of the-shaft adapted toengage and Itrip the -handleof a. wall lswitch after said slow movementof the piston and shaft Jover a predetermined distance.

`5. In a time delayattachment for -wallswitches of `the toggle type, -acylinder ihavinga-quantity of pressure fluid therein; :a piston slidablein the cylinder., .said piston having aaport forthe passage of fluidtherethrough and saidport ybeing of ra restricted .size .to 'slowmovement of the piston in one direction within the cylinder; a :seriesof check Aval-ved apertures inthe pistonarranged to permit free movementthereof in anzopposite direction; a shaft slidably mounted in.onefendiof the cylinder, said shaft Ahaving one endzportion extendinginto the cylinder and vloosely ,positioned through said port, forrslidable :mounting of the Ipiston on saidend portion of the shaft, saidend portion of the shaft having an elongated, axial .recess vand an.orifice communicating vbetween said recess and the-interior .of thecylinder through the side .wall .of .the shaft at .a Alocation spaced.from ,the adjacent vend of fthefshaft; an abutment on said end .portionof the shaft; 1a first spring circumposed .about the .shaft and seatedon said abutment, said lspring :being engageable by the piston afterslow movement of the piston along ythe shaft in said one .direction yapredetermined distance, ,f or effecting joint, slow movement ofthe shaftand piston thereafter in thegsame direction; a secondspring interposedbetween one .end of the cylinder and the piston, said second vspringbeing tensioned ,to ,urge the piston in said one direction; kand .meanson .the other endportionof .the shaftadapted to engage the handle vof avwallswitch after ,said joint, `slow movement of the piston and shaftovera predetermined distance, for Atemporarily.halting movement of the shaftduringcontinued movement .of said piston in the same directionYunderpressure `of the second spring, `said pistonl and orifice be-VVing'arranged for movement ofthe piston pastfthe :orifice after'saidtemporary halting of the shaft,

vwhereby Ato eiect movement of fluid past vthe pistonthrough both theport and orifice' 'and :thereby rdecrease the `resistance offered by thefluid to movement of the piston, thus to eiect trippingjof the handle bysaid means under vthe yproportionately increased pressure -of the secondspring Vagainstithezpiston.

l6. In atirnf,l del'ayattachmentfor-wall switches 'of fzthe'.togg1e1type, ya `cylinder yhaving a quantity vof pressure .fluidtherein; a cap detachably con vnected to fone end `of fthe cylinder; amounting plate adaptedto be'secured ytothe cover plate of a .wallswitch,'said cap and'mountingrplate havving `cooperating lmeans r`tordetachable connection :of :the 4capto the mounting'plate; a .pistonslidable in theicylinder, said'piston having a port for 'the passage .offluid -therethrough and said .portibeing of a restricted size to slowmovement `oft-'he piston in one-direction within the cylinder,

the piston havinga series of check valved aperitures arranged to .permitfree movement ofthe piston. `in ,an oppositezdirection; -a shaftslidably mounted in said cap, saidshafthaving. one end portion-fextending into the cylinder. and loosely positioned through saidiport,for slidable mounting of theipistonpn said endvportion of the shaft,said end. portion of the shaft having an elongated, axial-recess :and.an orice 'communicate ing vbetween saidrecess .and the interior of thecylinder througl'i the .side Wall .of `the shaft ,at aI :location spaced.from the adjacent end of the shaft; lanabutment on said end portieriof--the shaft; a first springcircumposed.about the shaft andseatedonesaid abutment, said spring being engageablefby the `pistonfafter slow movement of the `piston along vthe shaft in said onedirection, foreiectingnjoint, :slow movement of the shaft andypistonthereafter in the same directioneJ second spring interposedbetweenfthecap'andthe piston, said.secondzspringfbeing'tensioned to urge the pistonvin said one direction; fand a block pivotally `mounted on the-otherfend portionjof the shaft vand adapted Ito engage the handle of awallswitchafter said joint, slow movement of the piston andjshaft overa`predetermined distance, for temporarily haltingmovement ofthe shaftduringcontinued movement of `said Vpiston in the same .direction underpressure :of the second sprng,-said :piston .and oriice being arrangedfor movem'entzof the=piston past the-oriiice aftersaid temporary haltingof theshaft, whereby to effect movementtof fluid past lthe'fpistonthrough both the vport rand orifice and thereby decrease theresistanceoiered :by the fluid to movement 4of the piston, thus toeifect a tripping of the handle bysaid block under the proportionatelyincreased pressure ofthe second spring against the piston.

CLEMENT H. BRACKEN.

References Cited in the "file -of .this patent l 'STATES' PATENTSliillrnbervl`` u Dnmalll 31.11.18 7, 1909

